Electrical devices (e.g., x-ray tubes for computed tomography (CT) x-ray imaging systems) may use active switches to control the switching of the power source or supply for the devices (e.g., power source or supply for the x-ray tubes). For example, active switches are typically controlled by driving circuits using lower voltage signals, which may be implemented without much complexity when the switches are electrically referenced to ground. As the switches are electrically referenced to higher and higher voltages, however, more complex and bulky driving circuits are needed to allow the switches to turn on and off independent of each other. In these systems, particularly when the switches are referenced to different higher voltages, the control of the multiple switches includes switching equipment that is more complex and bulky (e.g., a large amount of fiber optics for communicating control signals, and large power supplies to send power to gate drivers at multiple isolated voltage references), adding size, complexity and cost to the overall system.
Known systems for controlling voltage switching, such as for controlling the voltage switching to an x-ray tube (e.g., fast kV switching for dual x-ray systems), may include isolated gate drives. These drives control the voltage switching to control the energy of the electron beam generated by the x-ray source, such as by controlling the voltage to the electron emission source and target of the x-ray tube. For example, CT imaging systems may comprise energy-discriminating (ED), multi-energy (ME), and/or dual-energy (DECT) imaging systems that may be referred to as an EDCT, MECT, and/or DECT imaging system. The EDCT, MECT, and/or DECT imaging systems are configured to measure energy-sensitive projection data. The energy-sensitive projection data may be acquired using multiple applied x-ray spectra by modifying the operating voltage of the x-ray tube or utilizing x-ray beam filtering techniques (e.g., energy-sensitive x-ray generation techniques), or by energy-sensitive data acquisition by the detector using energy-discriminating, or with photon counting detectors or dual-layered detectors (e.g., energy-sensitive x-ray detection techniques).
For example, with x-ray generation techniques, various system configurations utilize modification of the operating voltage of the x-ray tube including: (1) acquisition of different energy (e.g., low-energy and high-energy) projection data from two sequential scans of the object using different operating voltages of the x-ray tube, (2) acquisition of projection data utilizing rapid or fast switching of the operating voltage of the x-ray tube to acquire low-energy and high-energy information for an alternating subset of projection views, or (3) concurrent acquisition of energy-sensitive information using multiple imaging systems with different operating voltages of the x-ray tube.
The known drive controls for these systems may be referenced to multiple different high voltages (e.g., voltages more than ten kilovolts or a greater amount). When referenced to the high voltages, however, the conventional hardware to control the switching is physically large, thereby adding size, weight, and/or cost to the system. In some systems, the lack of space in the overall system may prevent implementation of these drive controls.
Additionally, known drive controls that are referenced to high voltages may require longer periods of time to dissipate any stored energy following the opening of switches or deactivation of loads controlled by the drive controls. This can limit how quickly the loads can operate and/or deactivate.